Method: TTY::Reader#read_line

Defined in:
lib/tty/reader.rb

#read_line(prompt = "", value: "", echo: true, raw: true, nonblock: false) ⇒ String

Get a single line from STDIN. Each key pressed is echoed back to the shell. The input terminates when enter or return key is pressed.

Parameters:

  • prompt (String) (defaults to: "") —

    the prompt to display before input

  • value (String) (defaults to: "") —

    the value to pre-populate line with

  • echo (Boolean) (defaults to: true) —

    whether to echo chars back or not, defaults to false

  • [Boolean] (Hash) —

    a customizable set of options

Returns:

  • (String) 


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# File 'lib/tty/reader.rb', line 248

def read_line(prompt = "", value: "", echo: true, raw: true, nonblock: false)
  line = Line.new(value, prompt: prompt)
  screen_width = TTY::Screen.width
  buffer = ""

  output.print(line)

  while (codes = get_codes(echo: echo, raw: raw, nonblock: nonblock)) &&
        (code = codes[0])
    char = codes.pack("U*")

    if EXIT_KEYS.include?(console.keys[char])
      trigger_key_event(char, line: line.to_s)
      break
    end

    if raw && echo
      clear_display(line, screen_width)
    end

    if console.keys[char] == :backspace || code == BACKSPACE
      if !line.start?
        line.left
        line.delete
      end
    elsif console.keys[char] == :delete || code == DELETE
      line.delete
    elsif console.keys[char].to_s =~ /ctrl_/
      # skip
    elsif console.keys[char] == :up
      line.replace(history_previous) if history_previous?
    elsif console.keys[char] == :down
      line.replace(history_next? ? history_next : buffer) if track_history?
    elsif console.keys[char] == :left
      line.left
    elsif console.keys[char] == :right
      line.right
    elsif console.keys[char] == :home
      line.move_to_start
    elsif console.keys[char] == :end
      line.move_to_end
    else
      if raw && code == CARRIAGE_RETURN
        char = "\n"
        line.move_to_end
      end
      line.insert(char)
      buffer = line.text
    end

    if (console.keys[char] == :backspace || code == BACKSPACE) && echo
      if raw
        output.print("\e[1X") unless line.start?
      else
        output.print(?\s + (line.start? ? "" : ?\b))
      end
    end

    # trigger before line is printed to allow for line changes
    trigger_key_event(char, line: line.to_s)

    if raw && echo
      output.print(line.to_s)
      if char == "\n"
        line.move_to_start
      elsif !line.end? # readjust cursor position
        output.print(cursor.backward(line.text_size - line.cursor))
      end
    end

    if [CARRIAGE_RETURN, NEWLINE].include?(code)
      buffer = ""
      output.puts unless echo
      break
    end
  end

  if track_history? && echo
    add_to_history(line.text.rstrip)
  end

  line.text
end